initial thoughts on creating test extension managers

manager.py

class TestExtensionManagerMixin(object):
    """Mixin base class for test extension managers."""

    def over(self, extensions):
        """Set the Extensions used by this manager.

        :param extensions: Pre-configured Extension instances to use
                           instead of loading them from entry points.
        :type extensions: list of :class:`~stevedore.extension.Extension`
        :returns: this extension manager instance to allow chaining on
                  the constructor

        """

        self.extensions = extensions
        return self

    def _load_plugins(self, invoke_on_load,
                      invoke_args,
                      invoke_kwds):
        return []


class TestExtensionManager(TestExtensionManagerMixin,
                           extension.ExtensionManager):
    pass

test_test_manager.py

from mock import Mock
from stevedore.tests.manager import TestExtensionManager
from stevedore.extension import Extension


test_extension = Extension('test_extension', None, None, None)


def test_manager_should_allow_name_access():
    em = TestExtensionManager('').over([test_extension])

    assert test_extension == em[test_extension.name]


def test_manager_should_call():
    em = TestExtensionManager('').over([test_extension])
    func = Mock()

    em.map(func)

    func.assert_called_once_with(test_extension)